Need-to-Know ACT Math Formulas (Barrons)All the important and most forgotten formulas needed to know for the ACT
Pythagorean theorem Correct Answer: a^2 + b^2 = c^2
Circumference of a circle Correct Answer: C= (3
...
Need-to-Know ACT Math Formulas (Barrons)All the important and most forgotten formulas needed to know for the ACT
Pythagorean theorem Correct Answer: a^2 + b^2 = c^2
Circumference of a circle Correct Answer: C= (3.14)(d)
Area of a circle Correct Answer: A=(3.14)(r^2)
distance formula Correct Answer: D=(r)(t)
arithmetic sequence formula (explicit) Correct Answer: an = a1 + (n - 1)d
Sum of arithmetic sequence Correct Answer: S = (n/2) (a1 +(a1+(n-1)d)) or S = (n/2) (a1 + an)
Geometric sequence formula Correct Answer: an=a1(r)^n-1
Geometric Series formula Finite Correct Answer: Sn = a1 (1-r^n) / (1-r)
Combination formula Correct Answer: nCr=n!/r!(n-r)
Permutation Correct Answer: nPr=n!/(n-r)!
parabola Correct Answer: y=a(x-h)^2+k
circle Correct Answer: (x-h)^2+(y-k)^2
ellipse Correct Answer: ((x-h)^2/a^2) + ((y-k)^2/b^2)= 1
hyperbola Correct Answer: ((x-h)^2/a^2) - ((y-k)^2/b^2)= 1
Inscribed angle Correct Answer: IA=central angle(or intercepted arc)/2
Property of Parallelogram Correct Answer: Opposite sides are parallel and congruent
opposite angles are congruent
consecutive angles are supplementary
diagonals bisect each other
Property of Rectangle Correct Answer: 4 90 degree angles
Property or Rhombus Correct Answer: 4 congruent sides
Property of Square Correct Answer: 4 90 degree angles and sides
Property of Trapezoid Correct Answer: one set of parallel sides
isosceles trapezoid Correct Answer: one set of parallel sides and 2 congruent sides
trigonometry functions Correct Answer: a sin (b(x-c))+d
area of trapezoid Correct Answer: a= (b1+b2/2)(h)
volume of a pyramid Correct Answer: B(length x width) x H
volume of a cone Correct Answer: (1/3)(pi)(r^2)(h)
volume of a cylinder Correct Answer: (pi)(r^2)(h)
volume of sphere Correct Answer: 4/3(pi)(r^3)
volume of rectangular prisim Correct Answer: b x w x h
sum of angles in polygon Correct Answer: n=(n-2)(180)
single interior angle Correct Answer: n= (n-2)(180)/n
[Show More]
